1. Field of the Invention
The present invention relates to a marine vessel propulsion device including a vapor pathway connecting a vapor separator tank to an intake system, and a valve disposed in the vapor pathway.
2. Description of Related Art
An outboard motor is an example of a marine vessel propulsion device. An outboard motor of one prior art is disclosed in U.S. Patent Application Publication No. US2005/0016504 A1. The outboard motor includes a vapor pathway connecting a vapor separator tank and an intake system, a valve interposed in the vapor pathway, and an engine controller which controls the valve. Fuel is supplied from a fuel tank to the vapor separator tank by a low pressure fuel pump. The fuel in the vapor separator tank is supplied to a fuel injection device (fuel injector) by a high pressure fuel pump.
The engine controller closes the valve while the engine is stopped, and controls the valve to gradually open the valve when starting the engine. Therefore, during operation of the engine, the valve is kept open. When the engine operates, the temperature of the fuel in the vapor separator tank is raised by radiation heat from the engine, and generates fuel vapor. The vapor is allowed to escape to the intake system through the vapor pathway, so that the vapor can be burned. When the engine is stopped, the engine controller closes the valve. Accordingly, when the engine is stopped, the vapor can be prevented from being allowed to escape to the outside.